AMD rides Bulldozers into the x86 server chip war

Opteron 6200s AND 4200s enter field against Xeon E5s

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The x86 lowdown

The Opteron 4200 chips have three x16 HyperTransport 3.0 links per socket running at 6.4GT/sec. They plug into the same C32 sockets as the Opteron 4100s, and the AMD chipsets used in conjunction with the chips can support one or two sockets in a single system image.

AMD has shifted back to thermal design point (TDP) ratings preferred by Intel to categorize its Xeon processors, and the Opteron 4200s are available in 95 watt standard parts, 65 watt Highly Efficient (HE) parts, and 35 watt Extremely Efficient (EE). The HE and EE parts run at lower voltages and lower clock speeds and therefore emit a lot less power. The TDP ratings are in the same thermal bands as the 75 watt, 50 watt, and 32 watt ACP-rated Opteron 4100. The chips come with six or eight cores, with the plain-vanilla chips running at between 2.7GHz and 3GHz. The Opteron 4200 HE parts spin at 2.5GHz with eight cores and 2.8GHz with six cores, and the eight-core EE part runs at 1.6GHz and hence doesn't run very hot.

But the new Turbo Core mode gives customers a potential 300MHz to 500MHz of extra performance if there is enough TDP headroom in the system, and if half the cores are put into a C6 sleep state then the remaining cores in the chip can deliver anywhere from 600MHz and 1GHz of performance over the rated clock speed of each chip. The burst-mode clock speed on the eight-core Opteron 4284 and six-core Opteron 4234 with half of their cores asleep is 3.7GHz. Here's how the Opteron 4200s line up against their predecessors:

AMD's Opteron 4200 processors versus the Opteron 4100s

The laws of thermodynamics won't let AMD cram two Opteron 4200s in a single package and keep all the same clock speeds - the heat density is too high and you have to slow down the clocks a bit so the chip doesn't melt. The Opteron 6200 package still runs quite a bit hotter than the Opteron 4200, with TDPs ranging from a low of 85 watts to a high of 140 watts with the Special Edition (SE) part.

The Interlagos package, which plugs into the existing G34 socket, also has one extra x16 HT 3.0 link per socket, which allows for the machine to scale up as far as four sockets in a single system image. You can also create two-socket Opteron 6200 machines. The Opteron 6200s have four memory channels per socket and up to three a dozen memory sticks for a total of 384GB per socket. That 1.5TB of memory for a four-socket box is a lot more competitive with Xeon alternatives than was the prior Opteron 6100s, which topped out at 512GB for a four-socket box.

Here's how the Opteron 6200s stack up against their predecessors:

The Opteron 6200s versus their 6100 precursors

Fruehe says that with the Interlagos chips, AMD concentrated on memory throughput and throwing lots of cores at it, and pointed out that an Opteron socket has four memory channels running at 1.6GHz compared to three channels running at 1.33GHz for the Intel Xeons. "All of the workloads that love lots of cores, lots of floating point, or lots of memory, are going to run well on these processors."

The Opteron 6200 processors have been shipping quietly to server OEMs since late August and are available today in volume quantities. (Fruehe says that over a half million Bulldozer cores have already shipped prior to announcement day.) Server vendors are expected to start rolling out support for the chips immediately. The Opteron 4200s will begin shipping in December. ®